In various conventional devices and apparatuses, a current detector detects a current, and control depending on a detection result is performed (for example, see Patent Documents 1 and 2).
In the above devices and apparatuses, when the current detector cannot accurately detect a current, control cannot be properly performed. For this reason, a failure of the current detector must be able to be detected.
FIG. 10 is a block diagram of a drive apparatus CC including a fault detecting apparatus 100 according to a conventional example. The drive apparatus CC is to supply a power and a drive signal to a load 210, and includes a fault detecting apparatus 100 having a control unit 110 and a current sensor 120, a drive circuit 310, and a current sensor 410.
The drive circuit 310 includes a switch element (not shown). The drive circuit 310 turns on/off the switch element depending on a control signal supplied from the control unit 110 to change outputs.
An output current from the drive circuit 310 changes depending on an on/off operation of the switch element, is detected by the current sensor 410, and is also detected by the current sensor 120. A detection result obtained by the current sensor 410 is sent to the control unit 110 as a first current detection value, and a detection result obtained by the current sensor 120 is sent to the control unit 110 as a second current detection value.
The control unit 110 generates a control signal depending on the first current detection value and transmits the control signal to the drive circuit 310. The control unit 110 compares the first current detection value with the second current detection value. When the values are different from each other, the control unit 110 determines that the current sensor 410 fails. For this reason, the failure of the current sensor 410 can be detected by the fault detecting apparatus 100.